Added ability to list users along with their roles. Moved the assign role/remove role methods to the user controller as they seem to belong there.
Deleted the Assessors controller as its better to be able to filter by any role rather than having a controller filtering a specific one.
Added error message if you try and filter by role without giving rolename.
Merge pull request #23 from cyrusinnovation/show-list-of-users

Show list of users